Field of the Disclosure
The present disclosure relates to a camera, an optical system and an interchangeable lens including a birefringent device, respectively. The disclosure further relates to a method of manufacturing an optical system.
Description of Related Art
When taking an image with a lens that limits the depth of focus, out-of-focus portions of the image appear unsharp or blurred. The subjective quality of how the out-of-focus portions appear to a viewer contributes to the overall image quality. The way the lens renders out-of-focus points of light is described by the term “bokeh”. For example, out-of-focus light points imaged into spots, in which brightness gradually and smoothly decreases with increasing distance to a centre point, result in smoothly blurred out-of-focus portions and a pleasant bokeh. Out-of-focus light points which the lens images into blurred spots in which brightness abruptly decreases or increases at a certain distance to the center point may result in hard edges within the blurred image portions or in rings which the viewer typically perceives as less pleasant, respectively. Determining factors for the type of bokeh are amount and sign of the optical aberrations present in the optical system.
There is a need for optical systems and cameras with pleasant bokeh. The object of the present embodiments is achieved by the subject-matter of the independent claims. The dependent claims define further embodiments.